Slag skimming apparatus

ABSTRACT

Apparatus for skimming slag from molten iron poured from a submarine ladle or the like is comprehended in a frame attachable to a submarine ladle in communication with the port thereof. The frame holds a diversion trough, into an end of which the iron is poured when the ladle is tilted, the diversion trough having perforations in its bottom, a collecting trough positioned below the diversion trough so as to receive the iron therefrom and direct it to a transfer ladle, and an open-end slag collecting basket positioned in the diversion trough having a skimmer lip at its open end. The perforations in the diversion trough retard the flow of iron sufficiently to maintain a dynamic pool of iron therein, which buoys the open end of the slag collecting basket so as to maintain its skimmer lip at a skimming level.

United States Patent [191 Meyers [451 June 4, 1974 [75] Inventor:

[52] US. Cl. 266/37, 266/38 [51] Int. Cl. F27d 3/14 [58] Field of Search266/37, 38, 39, l R

[56] References Cited UNITED STATES PATENTS 682,512 9/l90l Wellman266/38 Primary ExaminerGerald A. Dost Attorney, Agent, or FirmBuell,Ziesenheim Blenko &

[57] ABSTRACT Apparatus for skimming slag from molten iron poured from asubmarine ladle or the like is comprehended in a frame attachable to asubmarine ladle in communication with the port thereof. The frame holdsa diversion trough, into an end of which the iron is poured when theladle is tilted, the diversion trough having perforations in its bottom,a collecting trough positioned below the diversion trough so as toreceive the iron therefrom and direct it to a transfer ladle, and anopen-end slag collecting basket positioned in the diversion troughhaving a skimmer lip at its open end. The perforations in the diversiontrough retard the flow of iron sufficiently to maintain a dynamic poolof iron therein, which buoys the open end of the slag collecting basketso as to maintain its skimmer lip at a skimming level.

20 Claims, 5 Drawing Figures 1 SLAG SKIMMING APPARATUS This inventionrelates to apparatus for skimming slag from a stream of molten metal. Itis more particularly concerned with apparatus of this type adapted foruse with a submarine or torpedo ladle, so-called.

My invention is particularly adapted to the skimming of slag from thesurface of a stream of molten blast furnace iron and will be describedhereinafter in that context. My apparatus is suitable, however, forskimming slag from other metals, or for skimming any. lighter weightliquid from a stream of a heavier liquid.

Iron for steel making is smelted from its ores in blast furnaces, whichnow are built in capacities approaching 5,000 tons per 24 hour day.These furnaces are continuously charged, but are tapped at intervals ofa few hours so that each tap represents several hundred tons of iron.The slag resulting from this smelting is lighter than the iron andfloats thereon. Although it is flushed off from the blast furnace beforeeach tap, some slag always remains on the iron and is tapped out withthe iron into the iron runner. These runners are provided with slagskimming devices which divert most of this slag but some of it iscarried into the iron ladle.

The iron ladles transport iron to the steelmaking furnaces. It is quitecommon to use submarine or torpedo ladles, so-called, for this purpose,as they are made in large capacities and retain the heat of the ironbetter than open-top ladles. A submarine ladle, as the name implies, isan elongated cylindrical structure carried on railroad trucks, rotatableabout its axis. It has a covered port through which it is charged andthrough which, when it is rotated, it pours out its contents. Submarineladles normally pour their contents into transfer ladles which chargethe furnace with the iron and any slag which floats thereon. Iron ladlesare conventionally lippouring ladles which do not separate slag fromiron.

It is not desirable to charge blast furnace slag into steelmakingfurnaces. Blast furnace slag is very effective in desulfurizing iron inthe blast furnace, and is therefore high in sulfur. Under some furnaceoperating conditions, blast furnace slag is acid and is therefordetrimental to the basic linings of all tonnage steelmaking furnaces.Teapot spout ladles are sometimes used to separate iron from blastfurnace slag, but the slag remaining in such a ladle must be cleanedout. Prior to my invention to be described, no apparatus was known whichwas fully satisfactory in separating slag from iron poured from a ladle.

It is an object of my invention to provide apparatus auxiliary to asubmarine ladle adapted to skim slag from the stream of metal pouredfrom the ladle. It is another object to provide such apparatus whichsegregates the slag in a separate removable container. It is anotherobject to provide such apparatus which is detachably affixed to theladle. It is still another object to provide such apparatus whichutilizes the buoyancy forces of the flowing stream of metal tofacilitate the skimming of slag therefrom. Other objects of my inventionwill appear in the course of the description thereof which follows.

My apparatus comprises a frame which is rigidly attached to a submarineladle by a chain or other flexible means passed around the ladle andheld tight. The frame supports an intermediate trough into which theiron is poured when the ladle is tilted and from which the iron escapesthrough openings in the trough bottom, sized so that a dynamic pool ofiron is maintained in the trough. In this pool is positioned anopen-ended slag-collecting basket having a skimmer lip at its open endwhich skims the slag from the metal into the basket. The metal flowsbelow the basket and buoys or partially floats it so that the skimmer ispositioned at the proper skimming level. The slag-collecting basket isdetachable and removable.

An embodiment of my invention presently preferred by me is illustratedin the attached figures, to which reference is now made.

FIG. 1 is an elevation in cross-section through apparatus of myinvention attached to a submarine ladle;

FIG. 2 is a cross-section through the apparatus of FIG. 1 taken on theplane lIIl thereof;

FIG. 3 is a detail showing a modification of a portion of my apparatus;

, FIG. 4 is a schematic showing the various positions assumed by myapparatus as the submarine ladle is rotated to pour out its contents;and

FIG. 5 is a perspective of my apparatus.

A submarine ladle 10 of circular cross-section has a loading and pouringport surrounded by an upstanding circular collar 11. My apparatus iscomprehended in a frame 16 which comprises a front end piece 13 and rearend piece 14 which are parallel to each other and are spaced apart bytie rods 15-15. Front end piece 13 is formed with a port matching thatof ladle 10, which port is surrounded by a circular collar 17terminating in a flanged open end 18. This flanged opening 18 is adaptedto fit against collar 11 of submarine ladle 10.

Between end pieces 13 and 14 near their lower portions are positionedrefractory surfaced partitions 20 and 21, oppositely inclined so thattheir lower edges 22 and 23, respectively, define a narrowopeningextending from end piece 13 to end piece 14. Upper edges 24 and25, respectively, of partitions 20 and 21 are spaced apart the fullwidth of end pieces 13 and 14 so that those partitions form an openbottom V-shaped trough 27, which I denominate a collecting trough.Supported by upper portions 24 and 25 of partitions 20 and 21,respectively, and extending from end piece 13 to end piece 14 is arefractory surfaced arcuate concave-up trough 26 which I denominate adiversion trough. The lowermost portion of diversion trough 26 is flushwith or slightly below the lowermost point of collar 17. This diversiontrough is perforated through its bottom portion with slots 28-28 so thatmolten metal poured into diversion trough 26 through collar 17 flows outthrough slots 28-28 into collecting trough 27 and through the openbottom thereof.

Within diversion-trough 26 is positioned a refractory lined slagreceptacle or basket 30. This basket has a circular closed end 31adjacent frame end piece 14 and a wall 32 which extends to a regionshort of end piece 13. The inside surface of wall 32 is cylindrical butthe outside surface 38 is a section of a cone having a .greater diameterat its closed end 31 than at its other end. Basket 30 is open at thisend and is there fitted with a ring-shaped skimmer 33 which around itsouter surface 29 tapers to a relatively sharp lip 34 adjacent end piece13. The inside surface 35 of skimmer 33 is cylindrical and is of thesame diameter as the cylindrical inside surface of wall 32. The back end36 of skimmer 33 is formed as a tapered socket into which fits a 3tapered nose 37 formed on the front end of cylindrical wall 32.

Wall 32 of basket 30 is provided with a bail 39 adapted to receive acrane hook. Circular end 31 is supported for tilting movement therein bya semicircular ledge or shoulder 41 formed in end wall 14. That wallalso supports an air cylinder 42 on its rear face which is adapted tomove a pin 43 through wall 14 in and out of a recess 44 with clearance,formed at the center of circular end 31 of basket 30. A drain opening 50is provided in wall 32 adjacent end 31 and opposite bail 39. A stop 60projects from skimmer lip 34 90 from bail 39, and a like stop 90 in theother direction,

for a purpose to be described.

At the front end of frame 16 adjacent flange 18 are mounted like upperand lower fluid-operated cylinders 45-45 which are detachably connectedto like upper and lower saddles 46-46. The outside ends 48-48 of thosesaddles are connected to the two ends of chain 47 which encircles theshell of submarine ladle 10. The inside ends 49-49 bear against collar11. Each cylinder 45 is detachably connected to a saddle 46 by a hook 51intermediate ends 48 and 49. In the embodiment of FIG. 3, a ring-shapedskimmer 52 is fitted to the open end of cylindrical wall 32 of basket30. Skimmer 52 is formed with a cylindrical sleeve 53 which extendsinside wall 32.'The open end of wall 32 is bevelled at 54 to fit againsta shoulder 55 of skimmer 52 positioned intermediate its ends. Theoutside surface of skimmer 52 between shoulder 55 and its lip 57 is alsobevelled to form a prolongation of bevel 54. The inside end 58 ofskimmer 52 thus forms a ringshaped dam at the open end of wall 32.

The operation of my apparatus will be explained with reference to theforegoing description and the figures above mentioned.

My apparatus is positioned against a submarine ladle so that flange 18abuts the collar 11 surrounding the port of the ladle. My apparatus isheld in place by passing chain 47 around the shell of the ladle l0 andpulling it tight by admitting fluid under pressure to cylinders 45-45.The pull exerted by these cylinders on the outer ends 48-48 of thesaddles 46-46 also causes their inner ends 49-49 to exert pressure onthe collar 11, thus aligning it with collar 17 and flange 18. This Iattachment is effected with the ladle rotated so that its port andsurrounding collar 11 are upright, and my apparatus may be suspendedfrom a crane or otherwise supported to facilitate attachment.

The submarine ladle is then rotated about its axis a few degrees topermit iron to flow into my apparatus through the port surrounded bycollar 17. The relative positions of my apparatus and the ladle at thisstage are those marked A of FIG. 4. Initially, the front end of basket30 rests in diversion trough 26 and most of the iron coming from theladle flows out of diversion trough 26 vthrough'the slots 28 near thefront end piece 13. This flow of iron passing largely beneath the outersurface 29 of skimmer 33 tends to lift the skimmer and basket 30 at thatend so that the lip 34 of the skimmer 33 is automatically positioned atthe interface between the iron and the slag floating thereon. The closedend 31 of basket 30 tilts on shoulder 41 of end piece 14. The length ofcollar 17 is such that together with collar 1 1, it positions diversiontrough 26 far enough from the ladle that iron flowing out of the openbottom of collecting trough 27 clears the shell of the submarine ladle10. A transfer ladle, not shown, is positioned below my apparatus toreceive this iron.

As the iron level in the submarine ladle falls the ladle is rotatedfurther so as to move my apparatus into the position marked B in FIG. 4.More of the iron flows through the tapered gap between outer surface 38of basket and diversion trough 26 and out of the slots at the back endof diversion trough 26 exerting buoyant forces on basket 30 along agreater portion of its length. This tends to align inner surface tangentto the slag-metal interface plane so that slag will flow toward theclosed end 31 of basket 30. Continued rotation of the submarine ladlemoves my apparatus into position C and then into position D of FIG. 4,in which the bulk of the iron flows out of diversion trough 26 throughthe slots 28 near the rear end piece 14. However, the rear end 31 ofbasket 30 is restrained by pin 43 from rising, which limits any tendencyfor lip'34 of skimmer 33 to be moved below the slag-metal interface. Thestops 60 prevent basket 30 from sliding out of place. In its lowerposition, above mentioned, basket 30 of my apparatus holds largeramounts of slag. Some iron, of course, flows into the basket with theslag but it, being heavier than the slag, escapes through drain 50adjacent end wall 31.

Slag basket 30 need not be large enough to hold all the slag in thesubmarine ladle. A basket full of slag is easily removed from myapparatus by tilting the ladle back far enough to cut off the flow ofiron therefrom, withdrawing pin 43 from its socket 44 in end wall 31 ofbasket 30, and lifting basket 30 out of frame 16 by a crane hook throughbail 39. An empty basket is then dropped into place, and the submarineladle again tilted down to pouring position.

My apparatus is easily disconnected from the ladle after it has beenemptied. Pressure fluid is cut off from cylinders 45-45, allowingchain47 to slacken and relieving the pressure of the saddles 46-46 on collar11. One or both of cylinders 45-45 is disconnected from its saddle 46and hook 51 and chain47 pulled clear of ladle 10.

It is not essential that my apparatus be provided with fluid operatedcylinders 45 to attach it to a submarine ladle. The chain 47 may befitted with a turnbuckle or other known form of take-up for thispurpose. If permissible, the saddles 46 or similar devices may be weldedor otherwise permanently attached to the submarine ladle and if this isdone no chain is needed.

Although I find it convenient to make basket 30 circular incross-section and diversion trough 26 an arc of a circle incross-section, it is not necessary that these elements take thoseshapes, nor is it essential that other elements of my apparatus have theprecise configuration of my preferred embodiment.

In the foregoing specification I have described a presen'tly preferredembodiment of this invention, however, it will be understood-that thisinvention can be otherwise embodied within the scope of the followingclaims.

I claim:

1. Apparatus for separating floating slag from a stream of molten metalcomprising means for forming a dynamic pool of the metal, a slagreceptacle having an upstream open end and a downstream closed end, andmeans positioning the receptacle so that its open end is buoyed by thedynamic pool and so that it retains slag which flows into it.

2. Apparatus of claim 1 in which the bottom of the slag receptacle isarcuate in cross-section.

3. Apparatus of claim 1 in which the slag receptacle is an open endedcylinder.

4. Apparatus of claim 1 in which the inner wall surface of the slagreceptacle is cylindrical and the wall is thicker at the closed end ofthe receptacle than at its open end.

5. Apparatus of claim 1 including a relatively sharp lipped skimmeraffixed to the open end of the slag receptacle arranged to skim floatingslag off the molten iron into the slag receptacle.

6. Apparatus of claim 5 in which the underside of the skimmer isinclined away and downstream from its lip so as to direct molten metalbeneath the slag receptacle.

7. Apparatus of claim 5 in which the skimmer is detachably affixed tothe slag receptacle.

8. Apparatus of claim 5 in which the face of the skimmer adjacent theinside surface of the slag receptacle is flush therewith.

9. Apparatus of claim 5 in which the face of the skimmer adjacent theinside surface of the slag receptacle is higher than that inside surfaceso as to form a dam for slag within the slag receptacle.

10. Apparatus of claim 1 in which the means for forming a dynamic poolcomprise a diversion trough into an end of which metal is poured andopenings of restricted area extending through the bottom of thediversion trough so as to retard the flow of metal therethrough.

ll. Apparatus of claim in which the bottom of the diversion trough isarcuate in cross-section.

12. Apparatus of claim 10 including a collecting trough positioned belowthe diversion trough to receive metal which flows through the openingstherein.

13. Apparatus of claim 12 including a frame in which the diversiontrough and the collecting trough are fixed and means movably positioningthe slag receptacle in the frame.

14. Apparatus of claim 13 in which the means movably positioning theslag receptacle in the frame comprise a ledge which supports the closedend of the slag receptacle so as to permit the slag receptacle to tilton the ledge.

15. Apparatus of claim 13 including means affixed to the frame forreleasably retaining the closed end of the slag receptacle therein.

16. Apparatus of claim 13 including means for releasably clamping theframe to a ladle so that when the ladle is tilted iron poured therefromflows into the diversion trough.

17. Apparatus of claim 16 in which the means for releasably clamping theframe to a ladle include a chain surrounding the ladle connected at itsends to the frame.

18. Apparatus of claim 16 in which the means for releasably clamping theframe to a ladle include means for drawing the frame against the ladle.

19. Apparatus of claim 18 in which the means for drawing the frameagainst the ladle comprise fluid cylinder means.

20. Apparatus of claim 18 including saddle means attached to the meansfor drawing the frame against the ladle and disposed to bear on theladle so that the operation of the means for drawing the frame againstthe ladle increases the bearing pressure of the ladle means on theladle.

1. Apparatus for separating floating slag from a stream of molten metalcomprising means for forming a dynamic pool of the metal, a slagreceptacle having an upstream open end and a downstream closed end, andmeans positioning the receptacle so that its open end is buoyed by thedynamic pool and so that it retains slag which flows into it. 2.Apparatus of claim 1 in which the bottom of the slag receptacle isarcuate in cross-section.
 3. Apparatus of claim 1 in which the slagreceptacle is an open ended cylinder.
 4. Apparatus of claim 1 in whichthe inner wall surface of the slag receptacle is cylindrical and thewall is thicker at the closed end of the receptacle than at its openend.
 5. Apparatus of claim 1 including a relatively sharp lipped skimmeraffixed to the open end of the slag receptacle arranged to skim floatingslag off the molten iron into the slag receptacle.
 6. Apparatus of claim5 in which the underside of the skimmer is inclined away and downstreamfrom its lip so as to direct molten metal beneath the slag receptacle.7. Apparatus of claim 5 in which the skimmer is detachably affixed tothe slag receptacle.
 8. Apparatus of claim 5 in which the face of theskimmer adjacent the inside surface of the slag receptacle is flushtherewith.
 9. Apparatus of claim 5 in which the face of the skimmeradjacent the inside surface of the slag receptacle is higher than thatinside surface so as to form a dam for slag within the slag receptacle.10. Apparatus of claim 1 in which the means for forming a dynamic poolcomprise a diversion trough into an end of which metal is poured andopenings of restricted area extending through the bottom of thediversion trough so as to retard the flow of metal therethrough. 11.Apparatus of claim 10 in which the bottom of the diversion trough isarcuate in cross-section.
 12. Apparatus of claim 10 including acollecting trough positioned below the diversion trough to receive metalwhich flows through the openings therein.
 13. Apparatus of claim 12including a frame in which the diversion trough and the collectingtrough are fixed and means movably positioning the slag receptacle inthe frame.
 14. Apparatus of claim 13 in which the means movablypositioning the slag receptacle in the frame comprise a ledge whichsupports the closed end of the slag receptacle so as to permit the slagreceptacle to tilt on the ledge.
 15. Apparatus of claim 13 includingmeans affixed to the frame for releasably retaining the closed end ofthe slag receptacle therein.
 16. Apparatus of claim 13 including meansfor releasably clamping the frame to a ladle so that when the ladle istilted iron poured therefrom flows into the diversion trough. 17.Apparatus of claim 16 in which the means for releasably clamping theframe to a ladle include a chain surrounding the ladle connected at itsends to the frame.
 18. Apparatus of claim 16 in which the means forreleasably clamping the frame to a ladle include means for drawing theframe against the ladle.
 19. Apparatus of claim 18 in which the meansfor drawing the frame against the ladle comprise fluid cylinder means.20. Apparatus of claim 18 including saddle means attached to the meansfor drawing the frame against the ladle and disposed to bear on theladle so that the operation of the means for drawing the frame againstthe ladle increases the bearing pressure of the ladle means on theladle.